The present invention relates to a delivery unit having a level transmitter, and more particularly, to a lever transmitter for installation in a fuel tank, comprising a connection between a flange and a pump holder and provided with a spring against whose force the flange and the pump carrier are movable in a longitudinal direction of the delivery unit.
DE-OS 27 40 653 shows a liquid-level measuring device in which, via a longitudinal guide constructed on a fastening flange, a housing comprising a motor-driven pump arranged thereon is elastically supported on a fuel tank bottom. However, the longitudinal guide comprising two opposite oblong holes and a pin which can be displaced in the oblong holes disadvantageously permits only a longitudinal movement in the perpendicular direction. Therefor, compensation of tolerances or of deformations of the fuel tank is possible only in the perpendicular direction. Because of the long lever arms of the level transmitter fastened to the pump holder, however, even slight angle changes of the pump holders out of the intended position result in considerable measuring errors.
It is an object of the present invention to provide a delivery unit comprising a level transmitter in the case of which angle deviations from the desired position of the flange for the fastening of the delivery unit on the fuel tank and/or of the bottom of the fuel tank do not affect the measuring precision of the level transmitter arranged on the delivery unit.
This object has been achieved according to the present invention by providing that the connection between the flange and the pump holder is configured to be longitudinally movable and rotatable, and a lower end of the pump holder is swivellably centerable on a bottom of one of the fuel tank or of a baffle pot.
Because of the construction of the delivery unit according to the present invention as a complete preassembled unit, a fast mounting in the fuel tank in the correct position is achievable. The capacity of the delivery unit to be preassembled results in a compact construction which provides a simple transportability and storability. In addition, after the preassembling, a testing of the delivery unit is now advantageously possible with respect to both function and measuring precision of the level transmitter.
In an arrangement of the delivery unit according to the present invention in a baffle pot fastened in the fuel tank, as the result of the shape of the baffle pot and the correspondingly adapted shape of an end of the pump holder constructed as a supporting foot, a guide can be developed which prevents an incorrect mounting of the delivery unit in the baffle pot. Preferably, the shape of the baffle pot or, when a baffle pot is absent, of a corresponding construction on the bottom of the fuel hank and of the supporting foot is wedge-shaped or conical in the top view and/or circular in the lateral view as is also the same with a delivery unit in the case of which a baffle pot is integrated in the lower end of the pump holder. As a result of the space or the clearance between the lower end of the pump holder constructed as a supporting foot or baffle pot and the corresponding counterguide constructed on the fuel tank or on the baffle pot, a simple moving or swivelling of the fuel tank or the baffle pot about the lower end of the pump holder can be achieved.
Because of the construction according to the present invention of a spring-stressed longitudinally displaceable pivot bearing between the fastening flange and the upper end of the pump holder, the delivery unit is braced against the bottom of the fuel tank or of the baffle pot such that the delivery unit will always be in the desired installed position independently of the tolerances and deformations of the fuel tank.
As the result of the additional support of the delivery unit via the lower end of the pump holder configured as a supporting foot or as a baffle pot on the bottom of the fuel tank, a relieving of the flange seal and of the screwed connection is achieved. Advantageously, in the case of the delivery unit according to the invention, the fuel pump is disposed by way of a pump carrier and damping elements on or in the pump holder. The construction of the pump carrier itself and of the damping elements as well as their arrangement on the pump carrier may be effected in a conventional manner as, for example, according to DE-OS 39 27 218.